For patients with diabetes, there are two principal modes of daily insulin therapy. The first mode includes syringes and insulin pens. These devices are simple to use and are relatively low in cost, but they require a needle stick at each injection, typically three to four times per day. The second mode includes insulin infusion therapy, which utilizes an insulin pump. Infusion pumps, although more complex and expensive than syringes and pens, offer the advantages of continuous infusion of insulin via an infusion cannula, precision dosing, and programmable delivery schedules.
The use of an infusion pump requires the use of a disposable component, typically referred to as an infusion set, line set, extension set or pump set, which conveys the insulin from a reservoir within the pump into the skin of the user. An infusion set typically consists of a pump connector, a length of tubing, and a hub or base from which an infusion cannula (i.e., an infusion needle or a flexible catheter) extends. The hub or base has an adhesive which retains the base on the skin surface during use, and which may be applied to the skin manually or with the aid of a manual or automatic insertion device. In most cases, a detachable fluid connector is provided to allow the pump tubing to be disconnected from the hub or base of the infusion set when the user wishes to shower, bathe or swim.
A second way of providing insulin infusion therapy is by means of a patch pump. A patch pump is a self-contained device incorporating an insulin reservoir, pump and cannula in a single housing that can be adhered to the user's skin. A patch pump offers the advantage of not requiring the user to disconnect pump tubing when the user wishes to shower, bathe or swim.
A problem with infusion sets and patch pumps occurs when the cannula separates from the skin of the patient or becomes dislodged such that leakage occurs at the infusion site. Infusion pumps generally dispense insulin in small volumes for long periods of time. When leakage occurs, it is often not noticed by the patient for an extended length of time, resulting in an improper dosage.
Accordingly, there is a continuing need in the industry for improved infusion sets and patch pumps that provide adequate leak detection to the patient.